Voltage converters or inverters are widely used in power electronics or electrical engineering, to transfer power into power converters. Many applications where one or a plurality of voltage inverters, performing a DC/AC conversion, are used in conversion systems having any general conversion function (DC/DC, AC/AC, DC/AC or AC/DC) are known.
A particularly widespread category of converters concerns neutral point clamped (NPC) inverters. Typically, a voltage inverter of this type is based on the use of switching units formed of power switches, generally MOS transistors or IGBT transistors, assembled with capacitive elements.
The different components and their assembly are selected according to the voltage level (several hundred volts, or even in the order of one thousand or of a few thousand volts).
Document EP 2884650 describes a power unit comprising two elements and a three-level power conversion device, based on the replication of this unit. Each unit comprises two MOS transistors series-connected at the level of the drain of one of them and of the source of the other. The units are formed separately to be arranged in 3D, a unit being stacked on the two other units.
Document EP 2996233 describes a semiconductor device comprising two switching circuits respectively on IGBTs and diodes.
Document EP 0590502 describes an inverter device for electric rolling stock.